An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Possible mechanisms for generation of pandemic influenza viruses. [Reproduced with permission from ref.…
Figure 1
Possible mechanisms for generation of pandemic influenza viruses.
[Reproduced with permission from ref. (Copyright 1998, American
Society for Microbiology).]